A wide range of subcutaneous drug delivery devices is known.
Several years ago the needs of society in the medical field were different from today's needs and the technology abilities then were also different from modern technology. In the 1950's there was a very big need to treat diabetes mellitus with self-administered insulin injections. These needs were met by several devices, whose purpose was to allow a person to administer self injections of the drug at home. Such devices are disclosed, for example, by U.S. Pat. No. 2,660,169 titled “Devices for supporting and operating hypodermic syringes and injecting a fluid into the body”. The device is very simple, with no electronics in it, operated by manual pressure only. Its only function is to inject the whole contents of the syringe at once into the patient.
Later, in the 1970's another need arose—to vaccinate a large population in a short period of time. This need was addressed by “gun-like” injection devices, such as disclosed in U.S. Pat. No. 3,727,614, which discloses a multiple dosage inoculator for administrating vaccines, where the vacuum is used to draw the skin of the patient onto the needle using only one hand.
Another “gun-like” injection device adapted for the self-injection of insulin is disclosed in U.S. Pat. No. 4,067,334. This device is manually operated. The syringe is connected to a spring, that allows its movement, and a drug is injected by releasing the air pressure contained in the bulb, operated by the user.
Another field of the medicine/cosmetic treatments that was developed around the 1980's is mesotherapy. U.S. Pat. No. 4,108,177 discloses a gun-like device, operated by an electro-magnet and a motor. This is the first invention that uses an electric mechanism to create motion. The device is able to perform many injections in a short period of time, and create very fast syringe motion and very fast fluid injection.
U.S. Pat. No. 4,512,767 discloses a gun-like mesotherapy mechanical injection device, which includes means for positioning the penetration needle and to predetermine the degree of penetration of the needle.
U.S. Pat. No. 4,790,823 discloses another such device having an optical sight for a precise needle direction and a micro-controller for controlling the quantity of the injected fluid and the speed of injection.
U.S. Pat. No. 4,600,403 discloses a suction injector where an electric motor is used to create suction. The injection is triggered by the skin, as soon as it has been raised high enough and the amount of injected fluid is electronically controlled.
In U.S. Pat. No. 4,833,384 a motor is coupled to a lead screw that moves a syringe plunger whose position is accurately controlled by a digital encoder.
A very important factor in automatic injection devices is the need to control needle penetration depth. One solution is taught by U.S. Pat. No. 5,015,235 where the user selects an adjuster from a set of adjusters of different sizes and fits it over a part of a hub.
U.S. Pat. No. 5,690,618 discloses an electronic syringe for administrating anesthetic injections, particularly suited in dental applications where a precise level of hand control is required. A drive means is provided in electrical communication with an electronic controller, which controls the amount of the injected fluid and the injection flow rate.
U.S. Pat. No. Re. 35,986 discloses an automatic injector having two chambers containing different ingredients of medicament separated by a membrane and mixed during injection. Needle penetration depth is limited by placing a disc on the needle.
U.S. Pat. No. 5,906,592 discloses a device for accurately infusing fluids into a patient at specific rates over an extended period of time.
U.S. Pat. No. 5,921,962 discloses an injection device having a flow indicator that provides an indication at any given time about the amount of fluid remaining in the device.
U.S. Pat. No. 6,994,691 discloses an injection device for making injection at a predetermined depth in skin. A skin positioning member is positioned on a patch of skin within an area of skin such that at least a part of the patch of skin may be held elevated above or depressed below the area of skin. A guidance mechanism guides an injection needle to slide beneath the skin positioning member to an injection position.
As it can be seen in the prior art study, known injection devices are able to penetrate the skin perpendicularly, but they cannot perform a series of injections while controlling the distance between those injections; neither can they control the needle penetration speed. For all the reasons listed above, filler injection procedures are being performed manually.
The problem of the filler's manual injections methods used in today's practice is that the needle penetration is done in parallel to the skin surface. In that way consequently, it is very difficult to control the injection depth accurately and to control the amount of the injected drug/filler. Moreover, it is difficult or impossible to maintain the layer of the injected drug/filler under the skin surface uniform without lumps. Additionally, the procedure is painful owing to internal skin tissue tearing and patient bleeding due to the blood vessels injury. Also, it is difficult to avoid swelling, pain and redness following treatment.
Additionally, it emerges from the prior art review that there is a need for an advanced injection device able to control the speed of needle penetration into the skin. There is a need for the device to be able to control the depth of needle penetration, injection flow rate, and the volume of the injected fluid or gel.
There is a need for the device to be painless, able to perform a series of injections, to control the distance between those injections, and to be capable of computer control or/and manual control.
The present invention overcomes the disadvantages of the injection devices associated with prior art drug delivery devices, the disadvantages of the devices existing on today's market and the disadvantages of manual injecting of drugs or fillers.